PDAs (personal digital assistants) are known in the art. Such devices are used to store and organize data, such as phone numbers, addresses, and other contact data, as well as calendars and schedules, and are portable, hand held devices. They typically have an operating system such as Windows CE. Some models are able to communicate using the Internet Protocol. For example, Palm, Inc. has a service plan that provides users of PDAs, such as the Palm series of handheld computers, wireless access to Internet content and e-mail.
It is known in the art to combine Global Positioning System (GPS) receivers with personal digital assistants. See, for example, the following U.S. Patents, all of which are incorporated herein by reference: U.S. Pat. Nos. 5,675,524 to Bernard; 5,669,244 to Clark, Jr. et al.; and 5,528,248 to Steiner et al. By doing so, the personal digital assistant is able to provide position information to the user. Navigation functions allow the user to navigate to a desired location, carrying the personal digital assistant along the way. Moving maps can track a user's progress in real time and show landmarks.
Emergency response services are known in the art. When someone is experiencing an emergency, they dial 911 and the operator receives address information on a monitor. The address information is obtained, for example, using address information in a telephone company database associated with the caller's phone number. The 911 operator can dispatch emergency personnel even if the caller is unable to speak or to communicate address information.
Determining the location of a user of a cell phone or other mobile phone is obviously more difficult than determining the location of a user of a conventional wired telephone, because such phones are mobile. Yet various techniques are emerging for doing so. See, for example, the following U.S. Patents, all of which are incorporated herein by reference: U.S. Pat. Nos. 5,901,214 to Shaffer et al; 5,602,903 to LeBlanc et al.; 5,600,706 to Dunn et al.; 5,508,707 to LeBlanc et al.; and 5,479,479 to Braitberg et al. Cellular systems could be overhauled to locate a caller's position by equipping cell sites to locate cell phones using triangulation. Alternatively, cell phones could be equipped with GPS receivers. A decision by the Federal Communications Commission (FCC) expanded the definition of 911 to include cell phones and may result in increased use of GPS receivers in cell phones. Proponents of a handset-based approach to 911 believe that a handset-based approach can likely be deployed with more accuracy and lower cost than a network based triangulation system.
It is also known to incorporate 911 emergency communication access into pagers. See, for example, U.S. Pat. No. 5,894,591 to Tamayo, which is incorporated herein by reference.